Study selection

Studies were selected if they included children <5 years of age who received non-parental day care and if they used randomised
or quasi-randomised methods to allocate participants to groups.

Data extraction

Data were extracted on changes in children's developmental and intelligence quotients (IQ), school performance, behaviour,
and health and on maternal employment, fertility, and interaction with children.

Main results

8 studies of disadvantaged populations in the US met the inclusion criteria. Compared with no daycare, daycare led to increased
IQ at age 3 years (weighted mean difference [WMD] 14.4, 95% CI 12.3 to 16.4, 4 studies) and at age 5 …